There is known a prior art content discharge mechanism as a content discharge mechanism where a discharge outlet of the contents accommodated in a pump type container is provided on another fixing member different from the operation part in Japanese Patent No. 3177695. The following reference numbers with [ ] indicate those in the present reference.
In the '695 patent, a pressure body [15], a sealing body [14], and a large piston [23] are integrated, where once a user pushes down the pressure body, the operation part, the large piston is also moved downward.
Hereby, there is boosted the pressure of chemical in a space [B] between the large piston [23] and an elastic tube [22e] as the suction valve that blocks a transparent hole [22c1] in the small piston [22] relatively movable with respect to the large piston.
As the pressing-down operation of the pressure body [15] is performed several times to permit chemical pressure in the space [B] to rise to a predetermined value, the small piston [22] is pushed down by the pressure, resulting in conical-shaped step part [23c1] etc. a contact part (discharge valve) between both the pistons being separated. Hereby, the chemical in the space [B] is injected to a diseased part from the nozzle hole [16a1] of the nozzle [16] after passage through the separation part, shaft hole [23c], space [D].
The nozzle [16] is fixed to an adapter [13] integral with the container body [11] and so is prevented from moving even upon the pushing-down operation of the pressure body [15].
The content discharge mechanism of the pump type container described above is configured in such a way that the nozzle [16] equipped with the nozzle hole [16a1] is another member independent from the pressure body [15] and the nozzle is prevented from moving downward even upon the operation of the pressure body. This is user-friendly.
In contrast, in addition to the large piston [23] interlocking with the pressure body [15], there is provided the small piston [22] relatively vertically movable with respect to the former, presenting an action of the discharge valve by the contact and separation between these pistons. Further, the transparent hole [22c1] of the small piston [22] and an elastic tube [22e] blocking the transparent hole [22c1] act as the suction valve.
The discharge valve in the discharge mode is closed when the chemical in the space [B] is injected from the nozzle hole [16a1] to permit the pressure of the chemical in the space to be gradually reduced to a threshold or lower, and the operation changes to the discharge finishing mode. More specifically, following the reduction of the chemical pressure in the space the small piston [22] returns upward to close the shaft hole [23c] of the large piston [23], preventing the chemical from being injected.
The foregoing content discharge mechanism suffers from the problem that not only the suction valve but also the discharge valve are formed with the large piston [23] and the small piston [22] provided on the vertical upstream passage i.e. the downstream passage up to the nozzle hole [16a1] extending to the upstream passage does not include the valve member so that the entire structure is complicated and a flow of the chemical is not smooth.
Further, pressure of the chemical in the space [B] in the discharge mode is gradually reduced, so that injection finishing operation of the chemical (transition operation from the discharge mode to the discharge finishing mode) lacks sharpness.